Printers include those printers having a printer component, such as a printer paper-feed roller, whose position must be determined for accurate operation of the printer. Typically, an analog encoder having an encoder wheel is operatively connected to the printer paper-feed roller. A standard analog encoder produces channel A and B output signals in quadrature which are used to define a repeating cycle of four regions (a substantially linearly ascending region of the channel A output signal followed by a substantially linearly ascending region of the channel B output signal followed by a substantially linearly descending region of the channel A output signal followed by a substantially linearly descending region of the channel B output signal). The position of the component (i.e., the distance moved by the component) is determined at time t by the value of the output signal of the region corresponding to time t, as is known to those skilled in the art. The crossover from one region to the next or previous region occurs when the output signal of the one region reaches a fixed high crossover level or a fixed low crossover level as is understood by the artisan. The distance moved by the component while in a particular region is the distance moved from a previous position. The previous position is the position of the component when the appropriate output signal reached the appropriate fixed high or low crossover level to transition to the particular region. This method of calculating the distance moved by a component is subject to inaccuracies due to phase error between the two output signals, encoder resolution limits, encoder signal amplitude reduction at fast speeds, and defects such as inaccurate encoder mounting and ink spots on the encoder wheel.
What is needed is an improved method for determining the distance moved by a component which is operatively coupled to an analog encoder.